1. Field of the Invention
The present invention relates to a Digital Multimedia Broadcasting (DMB) service, and more particularly to a method for providing information regarding service linking between satellite and terrestrial DMB systems.
2. Description of the Related Art
As generally known in the art, DMB provides portable or vehicular receivers with various multimedia signals, including audio and video signals, in a digital mode. The DMB is classified into satellite DMB and terrestrial DMB according to the transmission means. The satellite DMB provides DMB terminals with programs via satellite waves on a nationwide basis. The terrestrial DMB provides broadcasts via sky wave VHF channel nos. 12 and 8.
Although the satellite DMB is currently incompatible with the terrestrial DMB, it is expected in the near future that a single receiver terminal will be able to receive both satellite and terrestrial DMB services. DMB receiver terminals incorporate the functions of mobile communication terminals.
FIG. 1 illustrates a conventional DMB receiver terminal for receiving services from a number of systems.
Referring to FIG. 1, the DMB receiver terminal 100 is connected to a mobile communication system 11 (e.g. WiBro), which supports wireless data communication, a terrestrial DMB system 12, and a satellite DMB system 13 so as to receive corresponding services from each of them.
In order to receive DMB services from the terrestrial DMB system 12 and satellite DMB system 13, as illustrated in FIG. 1, the DMB receiver terminal 100 is provided with an EPG (Electronic Program Guide), which contains information regarding broadcasts available from each broadcasting system.
Particularly, each broadcasting service has its own EPG.
Therefore, in order to receive all broadcasting services via a single DMB receiver terminal 100, the EPG of the terrestrial DMB system 12 must be combined with that of the satellite DMB system 13 so that a unified service can be provided based on similarity among programs.
In the case of a DMB service, the mobility of a service subscriber frequently affects the quality of service among broadcasting systems. Suppose that a service subscriber is on the move: signals from the terrestrial DMB system 12, which has been providing a service to the subscriber, gradually weaken until the service is no longer provided. However, signals from the satellite DMB system 13 may be strong enough to provide a normal service at another place, or vice versa.
If the subscriber has been watching a program, the subscriber would want to watch it without interruption, even through the subscriber is on the move. This requires a method for switching from the terrestrial DMB 12 to the satellite DMB 13 and seamlessly connecting to a corresponding program being broadcast by the satellite DMB 13.
Conventionally, each DMB system 12 and 13 provides the DMB receiver terminal 100 with its own EPG, which contains programming information. However, currently there is no correlation between EPGs of the different DMB broadcasting systems 12 and 13.
When the DMB receiver terminal 100 can no longer receive a program from the terrestrial DMB system 12 for some reasons that is being watched by the service subscriber, and the subscriber and wants to receive a corresponding program from the satellite DMB system 13, the terminal must determine if the corresponding program is available from the satellite DMB system 13 and search for channel information.
Therefore, a method is needed for efficiently linking programs of the terrestrial and satellite DMB systems 12 and 13 so that corresponding services from both systems can be identified and switching between services can be accomplished so that services can be received from both systems.